scholarly journals Vasodilator-stimulated phosphoprotein restricts cell-to-cell spread of Shigella flexneri at the cell periphery

Microbiology ◽  
2015 ◽  
Vol 161 (11) ◽  
pp. 2149-2160 ◽  
Author(s):  
Soo Young Lee ◽  
Frank B. Gertler ◽  
Marcia B. Goldberg
Keyword(s):  
Shigella Flexneri ◽  
Cell Periphery ◽  
Cell Spread

scholarly journals Spatial, Temporal, and Functional Assessment of LC3-Dependent Autophagy inShigella flexneriDissemination

2018 ◽  
Vol 86 (8) ◽  
Author(s):  
Erin Weddle ◽  
Hervé Agaisse
Keyword(s):  
Colonic Mucosa ◽  
Defense Mechanism ◽  
Positive Impact ◽  
Shigella Flexneri ◽  
Wild Type ◽  
Content Type ◽  
Cell Defense ◽  
Membrane Protrusions ◽  
Cell Spread

ABSTRACTShigella flexneridisseminates within the colonic mucosa by displaying actin-based motility in the cytosol of epithelial cells. Motile bacteria form membrane protrusions that project into adjacent cells and resolve into double-membrane vacuoles (DMVs) from which the bacteria escape, thereby achieving cell-to-cell spread. During dissemination,S. flexneriis targeted by LC3-dependent autophagy, a host cell defense mechanism against intracellular pathogens. TheS. flexneritype III secretion system effector protein IcsB was initially proposed to counteract the recruitment of the LC3-dependent autophagy machinery to cytosolic bacteria. However, a recent study proposed that LC3 was recruited to bacteria in DMVs formed during cell-to-cell spread. To resolve the controversy and clarify the role of autophagy inS. flexneriinfection, we tracked dissemination using live confocal microscopy and determined the spatial and temporal recruitment of LC3 to bacteria. This approach demonstrated that (i) LC3 was exclusively recruited to wild-type oricsBbacteria located in DMVs and (ii) theicsBmutant was defective in cell-to-cell spread due to failure to escape LC3-positive as well as LC3-negative DMVs. Failure ofS. flexnerito escape DMVs correlated with late LC3 recruitment, suggesting that LC3 recruitment is the consequence and not the cause of DMV escape failure. Inhibition of autophagy had no positive impact on the spreading of wild-type oricsBmutant bacteria. Our results unambiguously demonstrate that IcsB is required for DMV escape during cell-to-cell spread, regardless of LC3 recruitment, and do not support the previously proposed notion that autophagy countersS. flexneridissemination.

scholarly journals Formate PromotesShigellaIntercellular Spread and Virulence Gene Expression

mBio ◽  
2018 ◽  
Vol 9 (5) ◽  
Author(s):  
Benjamin J. Koestler ◽  
Carolyn R. Fisher ◽  
Shelley M. Payne
Keyword(s):  
Gene Expression ◽  
Epithelial Cells ◽  
Host Cell ◽  
Shigella Flexneri ◽  
Virulence Gene ◽  
Plaque Size ◽  
Acid Fermentation ◽  
Content Type ◽  
Virulence Gene Expression ◽  
Cell Spread

ABSTRACTThe intracellular human pathogenShigella flexneriinvades the colon epithelium, replicates to high cell density within the host cell, and then spreads to adjacent epithelial cells. WhenS. flexnerigains access to the host cytosol, the bacteria metabolize host cytosolic carbon using glycolysis and mixed acid fermentation, producing formate as a by-product. We show thatS. flexneriinfection results in the accumulation of formate within the host cell. Loss of pyruvate formate lyase (PFL; ΔpflB), which converts pyruvate to acetyl coenzyme A (CoA) and formate, eliminatesS. flexneriformate production and reduces the ability ofS. flexnerito form plaques in epithelial cell monolayers. This defect in PFL does not decrease the intracellular growth rate ofS. flexneri; rather, it affects cell-to-cell spread. TheS. flexneriΔpflBmutant plaque defect is complemented by supplying exogenous formate; conversely, deletion of theS. flexneriformate dehydrogenase genefdnGincreases host cell formate accumulation andS. flexneriplaque size. Furthermore, exogenous formate increases plaque size of the wild-type (WT)S. flexneristrain and promotesS. flexnericell-to-cell spread. We also demonstrate that formate increases the expression ofS. flexnerivirulence genesicsAandipaJ. IntracellularS. flexneriicsAandipaJexpression is dependent on the presence of formate, andipaJexpression correlates withS. flexneriintracellular density during infection. Finally, consistent with elevatedipaJ, we show that formate altersS. flexneri-infected host interferon- and tumor necrosis factor (TNF)-stimulated gene expression. We propose thatShigella-derived formate is an intracellular signal that modulates virulence in response to bacterial metabolism.IMPORTANCEShigellais an intracellular pathogen that invades the human host cell cytosol and exploits intracellular nutrients for growth, enabling the bacterium to create its own metabolic niche. ForShigellato effectively invade and replicate within the host cytoplasm, it must sense and adapt to changing environmental conditions; however, the mechanisms and signals sensed byS. flexneriare largely unknown. We have found that the secretedShigellametabolism by-product formate regulatesShigellaintracellular virulence gene expression and its ability to spread among epithelial cells. We propose thatShigellasenses formate accumulation in the host cytosol as a way to determine intracellularShigelladensity and regulate secreted virulence factors accordingly, enabling spatiotemporal regulation of effectors important for dampening the host immune response.

scholarly journals Shigella applies molecular mimicry to subvert vinculin and invade host cells

2006 ◽  
Vol 175 (3) ◽  
pp. 465-475 ◽  
Author(s):  
Tina Izard ◽  
Guy Tran Van Nhieu ◽  
Philippe R.J. Bois
Keyword(s):  
Host Cell ◽  
Binding Sites ◽  
Type Iii Secretion ◽  
Molecular Mimicry ◽  
Shigella Flexneri ◽  
Cell Entry ◽  
Host Cells ◽  
General Mechanism ◽  
Host Cell Entry ◽  
Cell Spread

Shigella flexneri, the causative agent of bacillary dysentery, injects invasin proteins through a type III secretion apparatus upon contacting the host cell, which triggers pathogen internalization. The invasin IpaA is essential for S. flexneri pathogenesis and binds to the cytoskeletal protein vinculin to facilitate host cell entry. We report that IpaA harbors two vinculin-binding sites (VBSs) within its C-terminal domain that bind to and activate vinculin in a mutually exclusive fashion. Only the highest affinity C-terminal IpaA VBS is necessary for efficient entry and cell–cell spread of S. flexneri, whereas the lower affinity VBS appears to contribute to vinculin recruitment at entry foci of the pathogen. Finally, the crystal structures of vinculin in complex with the VBSs of IpaA reveal the mechanism by which IpaA subverts vinculin's functions, where S. flexneri utilizes a remarkable level of molecular mimicry of the talin–vinculin interaction to activate vinculin. Mimicry of vinculin's interactions may therefore be a general mechanism applied by pathogens to infect the host cell.

scholarly journals Mycobacterium marinum Escapes from Phagosomes and Is Propelled by Actin-based Motility

2003 ◽  
Vol 198 (9) ◽  
pp. 1361-1368 ◽  
Author(s):  
Luisa M. Stamm ◽  
J. Hiroshi Morisaki ◽  
Lian-Yong Gao ◽  
Robert L. Jeng ◽  
Kent L. McDonald ◽  
...  
Keyword(s):  
Actin Polymerization ◽  
Shigella Flexneri ◽  
Mycobacterium Marinum ◽  
Cytoskeletal Proteins ◽  
Intracellular Pathogens ◽  
Rickettsia Rickettsii ◽  
Direct Cell ◽  
Living Organisms ◽  
Syndrome Protein ◽  
Cell Spread

Mycobacteria are responsible for a number of human and animal diseases and are classical intracellular pathogens, living inside macrophages rather than as free-living organisms during infection. Numerous intracellular pathogens, including Listeria monocytogenes, Shigella flexneri, and Rickettsia rickettsii, exploit the host cytoskeleton by using actin-based motility for cell to cell spread during infection. Here we show that Mycobacterium marinum, a natural pathogen of fish and frogs and an occasional pathogen of humans, is capable of actively inducing actin polymerization within macrophages. M. marinum that polymerized actin were free in the cytoplasm and propelled by actin-based motility into adjacent cells. Immunofluorescence demonstrated the presence of host cytoskeletal proteins, including the Arp2/3 complex and vasodilator-stimulated phosphoprotein, throughout the actin tails. In contrast, Wiskott-Aldrich syndrome protein localized exclusively at the actin-polymerizing pole of M. marinum. These findings show that M. marinum can escape into the cytoplasm of infected macrophages, where it can recruit host cell cytoskeletal factors to induce actin polymerization leading to direct cell to cell spread.

Shigella flexneri subverts host polarized exocytosis to enhance cell‐to‐cell spread

2021 ◽  
Author(s):  
Thilina U.B. Herath ◽  
Arpita Roy ◽  
Antonella Gianfelice ◽  
Keith Ireton
Keyword(s):  
Shigella Flexneri ◽  
Cell Spread ◽  
Polarized Exocytosis

WIPF2 promotes Shigella flexneri actin‐based motility and cell‐to‐cell spread

2019 ◽  
Vol 21 (12) ◽  
Author(s):  
Céline Michard ◽  
Lauren K. Yum ◽  
Hervé Agaisse
Keyword(s):  
Shigella Flexneri ◽  
Cell Spread

CELL-TO-CELL SPREAD OF SHIGELLA FLEXNERI

1995 ◽  
Vol 20 (2) ◽  
pp. 235
Author(s):  
Billy Bourke ◽  
Philip Sherman
Keyword(s):  
Shigella Flexneri ◽  
Cell Spread

scholarly journals Key Role for DsbA in Cell-to-Cell Spread ofShigella flexneri, Permitting Secretion of Ipa Proteins into Interepithelial Protrusions

2000 ◽  
Vol 68 (11) ◽  
pp. 6449-6456 ◽  
Author(s):  
Jun Yu ◽  
Bryn Edwards-Jones ◽  
Olivier Neyrolles ◽  
J. Simon Kroll
Keyword(s):  
Confocal Microscopy ◽  
Disulfide Bond ◽  
Active Site ◽  
Shigella Flexneri ◽  
Wild Type ◽  
Pathogenic Potential ◽  
Previous Demonstration ◽  
Intercellular Spread ◽  
Cell Spread

ABSTRACT DsbA, a disulfide bond catalyst, is necessary for realization of the pathogenic potential of Shigella flexneri. Sh42, a mutant strain differing from wild-type M90TS solely because it expresses nonfunctional DsbA33G (substitution for 33C at the active site), secreted less IpaB and IpaC than M90TS in response to various stimuli in vitro. A kinetic study demonstrated that Sh42 responded more slowly to Congo red than M90TS. By modulating relative concentrations of functional and nonfunctional DsbA within bacteria, functional enzyme has been shown to be necessary for intercellular spread. By confocal microscopy, M90TS dividing in protrusions was shown to secrete Ipa proteins from the septation furrow, anticipating lysis of protrusions, while Sh42 showed minimal Ipa secretion in this location. In the light of a previous demonstration that DsbA is not necessary for entry of epithelial cells, we conclude that a role in virulence of this disulfide bond catalyst lies in facilitating secretion of Ipa proteins specifically within epithelial protrusions, in turn allowing cell-to-cell spread of S. flexneri.

scholarly journals Contribution of the Periplasmic Chaperone Skp to Efficient Presentation of the Autotransporter IcsA on the Surface of Shigella flexneri

2008 ◽  
Vol 191 (3) ◽  
pp. 815-821 ◽  
Author(s):  
Jennifer K. Wagner ◽  
Jason E. Heindl ◽  
Andrew N. Gray ◽  
Sumita Jain ◽  
Marcia B. Goldberg
Keyword(s):  
Outer Membrane ◽  
Shigella Flexneri ◽  
Critical Role ◽  
Amino Terminus ◽  
Primary Role ◽  
Membrane Anchor ◽  
Bacterial Surface ◽  
Periplasmic Chaperone ◽  
Cell Spread

ABSTRACT IcsA is an outer membrane protein in the autotransporter family that is required for Shigella flexneri pathogenesis. Following its secretion through the Sec translocon, IcsA is incorporated into the outer membrane in a process that depends on YaeT, a component of an outer membrane β-barrel insertion machinery. We investigated the role of the periplasmic chaperone Skp in IcsA maturation. Skp is required for the presentation of the mature amino terminus (alpha-domain) of IcsA on the bacterial surface and contributes to cell-to-cell spread of S. flexneri in cell culture. A mutation in skp does not prevent the insertion of the β-barrel into the outer membrane, suggesting that the primary role of Skp is the folding of the IcsA alpha-domain. In addition, the requirement for skp can be partially bypassed by disrupting icsP, an ortholog of Escherichia coli ompT, which encodes the protease that processes IcsA between the mature amino terminus and the β-barrel outer membrane anchor. These findings are consistent with a model in which Skp plays a critical role in the chaperoning of the alpha-domain of IcsA during transit through the periplasm.

scholarly journals Escape of Actively Secreting Shigella flexneri from ATG8/LC3-Positive Vacuoles Formed during Cell-To-Cell Spread Is Facilitated by IcsB and VirA

mBio ◽  
2015 ◽  
Vol 6 (3) ◽  
Author(s):  
François-Xavier Campbell-Valois ◽  
Martin Sachse ◽  
Philippe J. Sansonetti ◽  
Claude Parsot
Keyword(s):  
Actin Polymerization ◽  
Shigella Flexneri ◽  
Host Cells ◽  
Content Type ◽  
Single Membrane ◽  
Bacterial Uptake ◽  
Membrane Compartments ◽  
Autophagy Pathway ◽  
Type 3 ◽  
Cell Spread

ABSTRACTThe enteropathogenic bacteriumShigella flexneriuses a type 3 secretion apparatus (T3SA) to transfer proteins dubbed translocators and effectors inside host cells, inducing bacterial uptake and subsequent lysis of the entry vacuole. Once in the cytoplasm, the outer membrane protein IcsA induces actin polymerization, enabling cytoplasmic movement and cell-to-cell spread of bacteria. During this infectious process,S. flexneriis targeted by ATG8/LC3. The effector IcsB was proposed to inhibit LC3 recruitment by masking a region of IcsA recognized by the autophagy pathway component ATG5. The effector VirA, a GTPase-activating protein (GAP) for Rab1, was also shown to prevent LC3 recruitment. However, the context of LC3 recruitment aroundS. flexneriis not fully understood. Here, we show that LC3 is recruited specifically around secreting bacteria that are still present in vacuoles formed during entry and cell-to-cell spread. While LC3 recruitment occurs around a small proportion of intracellular wild-type bacteria, theicsB,virA, andicsB virAmutants display incremental defaults in escape from LC3-positive vacuoles formed during cell-to-cell spread. Our results indicate that IcsB and VirA act synergistically to allow bacteria to escape from LC3-positive vacuoles by acting at or in the immediate vicinity of the vacuole membrane(s). We also demonstrate that LC3 is recruited around bacteria still present in the single-membrane entry vacuole, in a manner akin to that seen with LC3-associated phagocytosis. Our results indicate that LC3 recruitment occurs around bacteria still, or already, in membrane compartments formed during entry and cell-to-cell spread, and not around bacteria free in the cytoplasm.IMPORTANCEThe targeting ofS. flexneriby LC3 is a classic example of the targeting of foreign cytoplasmic particles by autophagy (so-called “xenoautophagy”). It is often assumed that LC3 is recruited around bacteria present in the cytoplasm through the formation of canonical double-membrane autophagosomes. Our results indicate that LC3 is recruited around the entry vacuole composed of a single membrane as in the case of LC3-associated phagocytosis. Effectors IcsB and VirA had been implicated in the blocking of LC3 recruitment, but it was not known if they acted on the same or distinct LC3-recruiting pathways. Our results indicate that LC3 is recruited exclusively around bacteria present in vacuoles formed during entry and cell-to-cell spread and that both IcsB and VirA intervene at the latter stage to facilitate bacterial escape. Our report reconciles several findings and may have broad implications for our understanding of the specific targeting of bacterial pathogens by LC3.

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